1. Field of the Invention
The present invention relates to a relay device having more than one mechanical relay.
2. Description of Related Art
According to a conventional relay device described in Japanese Patent No. 4070481, mechanical relays are packaged on a bus bar. A loading circuit for passing an electric current through an external load and a coil circuit for passing an electric current through a coil of the mechanical relay are formed on this bus bar.
According to a conventional relay device described in JP-A-2005-142256, mechanical relays are packaged on a bus bar, and a control circuit for controlling energization of a coil of the mechanical relay is packaged on a printed board. A part of the bus bar is bent into many tabs and an end of the tab is connected to the printed board, so that the bus bar and the printed board are electrically connected.
However, the conventional relay device described in Japanese Patent No. 4070481 needs to use a bus bar having a thickness in accordance with a great current flowing through the loading circuit. On the other hand, an electric current flowing through the coil circuit is small. Accordingly, the coil circuit needs to be as thin as possible to decrease a space used by the coil circuit. Nevertheless, the working of the bus bar becomes difficult when the coil circuit is made thin.
In the conventional relay device described in JP-A-2005-142256, the tab connecting the bus bar and the printed board needs to be formed, and a bending process is necessary to form the tab.